Hot melt adhesives are widely used in industry for various packaging applications. Most such applications require that the adhesive have a fast set time, good machinability, and good bond aging properties. In addition, it is desirable that the adhesive maintain bonds over as broad a temperature range as possible.
Most hot-melt adhesives are based on polyethylene or ethylene-vinyl acetate copolymer. Polyethylene and chemically modified polyethylene based formulas tend to have excellent elevated temperature properties, while ethylene-vinyl acetate based adhesives tend to have very good low temperature properties. The choice of which of these two adhesives to use sometimes depends upon the needed properties of the final end use. Blending of polyethylene or chemically modified polyethylene with ethylene-vinyl acetate to obtain broader temperature properties is often not very effective because of compatibility problems. Therefore, a hot melt adhesive for packaging applications having good bond strength over a broad temperature has not been possible.
In light of the above, it would be desirable to be able to produce a hot melt adhesive having good bond strength at elevated temperatures and at low temperatures in order for the adhesive to be utilized in a broad array of applications.